My 101 Scout Cannonball Build

[T. Cotten]

If you trust the spec sheet, Dana,

Then you can determine the resulting factor of your new assembly by hanging the wheels and bare rods upon your beams, and adding weights to the rod tops until it achieves balance.

The added weight plus the rod tops then divided by the actual reciprocating weight gives you the existing factor.

Then decide if you want to change it; Please remember that the noble grace of a single-throw V twin is that it will run quite smooth over a wide range of factors. Motor balancing is for the motor's benefit, not the rider.

....Cotten

[d_lasher]

>> 68% is the first time I ever heard a factor for 101s, just like most other machines.
>> Sounds good to me because just about anything works (as long everything else is in order).

It’s the only number I was able to find. I found it on another board, about ten years old. He responded later and said the bike ran great. The other reason I thought I’d use 68 is if I don’t like it. I can take the motor apart and drill more holes to lower it. If I start to small I’d have to add weight back in.

>> So I suggest estimating what it came with if you can, and determining what you've got as is, before eating metal.
I’m on the road right now, when I get back I will. I’m not sure what that’s going to tell me. The pistons I pulled out were aluminum and the rods looked original. And unfortunately the bike was a basket case when I got it and the owner sadly was long gone. So I don’t know how it was used or how it ran. I’ll look harder when I get home.

>>
Can you weigh your rod tops?

I cheated, the rods came with a spec sheet, weights, lengths, bores. I have the weights but they’re at home.

>> Kitabel..
I’ll take my time a do everything you suggested. I can use the depth gauge to verify the depth of the drills. And an angle wheel to put the holes in the same spot on both wheels. And as always, measure, measure, and measure some more.

Cotten, I agree there’s no way I’m taking metal off of the connecting rods.

At the end of the day, even though it’s just a number I’d like to at least try for better then just throw it all together and hope for the best.

Thanks,
Dana

[T. Cotten]

I suspect that some "unsuccessful" (some vibration remains) balance jobs are not due to a bad choice of factor, but of:
1. wheels are not true
2. rod(s) are bent
3. unreasonably high cruising RPM
4. balance factor not applied equally as to metal removed and position (as my previous post), this includes (very slightly) holes not drilled to the same depth.

Calculations based on weight are, IMHO, deconstruction of what has already worked. An illustration: from front piston position 45° BTDC to TDC and 45° BBDC to BDC, the front and rear pistons are moving in opposite directions, and their exact vectors are affected by rod ratio. Neither of these are included in any balance formula.

Absolutely, Kitabel!

Kinda meant that with 'everything else in order'..

And yes, yes,.. motor 'balancing' is only a practical technique, not really science.

....Cotten
PS: But the #4 'position' thing confuses me: How then did the MOCO successfully run huge left flywheels?


And #3,.. For some reason my Pans always preferred to scream. (Loved Eisenhower's Interstates.)
It was like an aircraft 'humm' at seventy with 22-tooth motor and tranny sprockets and a hack.

PPS: I almost forgot!
There are experts who proclaim that the female rod 'top' should be shaved to what they feel is equal to the male, in spite of what you describe: masses moving in "opposite" directions.
Good thing these things are forgiving...

[kitabel]

I suspect that some "unsuccessful" (some vibration remains) balance jobs are not due to a bad choice of factor, but of:
1. wheels are not true
2. rod(s) are bent
3. unreasonably high cruising RPM
4. balance factor not applied equally as to metal removed and position (as my previous post), this includes (very slightly) holes not drilled to the same depth.

Calculations based on weight are, IMHO, deconstruction of what has already worked. An illustration: from front piston position 45° BTDC to TDC and 45° BBDC to BDC, the front and rear pistons are moving in opposite directions, and their exact vectors are affected by rod ratio. Neither of these are included in any balance formula.Flywheel balance X-section-2.JPG

[T. Cotten]

Thanks, that was one of my questions and it does make sense. I do have more questions about balancing. I feel like the old trick of balancing the flywheel with both rods and one piston isn't right when my pistons are aluminum and weigh a lot less now then the old factory pistons. So I'm thinking, and I almost hate to bring it up, of weighing everything and just using a balance factor of 68%. I searched online and somewhere, someone said 101 scouts had a factory balance of 68%.

My thoughts are I'm looking for a slow, reliable ride and the higher factor would give a better general purpose ride. The last thing I want is a drag racer. Does this make sense? If I use these numbers I end up using the two rods, one piston and an extra 30 grams.

Fine print, by piston I do mean piston, rings, clips and pin.

When I hang this up on the balance beam I'm off by a lot. I figure I'd have to drill 7 to 8 holes? Does that seem right?

Wow Dana!

68% is the first time I ever heard a factor for 101s, just like most other machines.
Sounds good to me because just about anything works (as long everything else is in order).

It would be great to back calculate the real thing, for History's sake,..

So I suggest estimating what it came with if you can, and determining what you've got as is, before eating metal.
(Sometimes its better to stuff'n'plug, and stuff.)

Can you weigh your rod tops?

....Cotten

[tfburke3]

You may find Jim Moshers site performanceindian.com interesting.Although his speed records are on newer scout power the info in the tech talk lower ends section would apply to a 101 also I beleive.
Tom

[kitabel]

I agree, the "total the components" is not valid if significant weight changes have been made.
What % factor would I use in a 101? I would shamelessly copy whatever some known expert has used successfully. Anything else could be an expensive experiment.

[d_lasher]

Thanks, that was one of my questions and it does make sense. I do have more questions about balancing. I feel like the old trick of balancing the flywheel with both rods and one piston isn't right when my pistons are aluminum and weigh a lot less now then the old factory pistons. So I'm thinking, and I almost hate to bring it up, of weighing everything and just using a balance factor of 68%. I searched online and somewhere, someone said 101 scouts had a factory balance of 68%.

My thoughts are I'm looking for a slow, reliable ride and the higher factor would give a better general purpose ride. The last thing I want is a drag racer. Does this make sense? If I use these numbers I end up using the two rods, one piston and an extra 30 grams.

Fine print, by piston I do mean piston, rings, clips and pin.

When I hang this up on the balance beam I'm off by a lot. I figure I'd have to drill 7 to 8 holes? Does that seem right?

[kitabel]

Congratulations on the progress and accumulated wisdom.
On the balancing: many motors removed from service will show holes drilled into the outer faces of the flywheels, since this is all that's available when they're assembled.
However, any weight removal should be in the inner faces only. Not really practical, this includes filling in any outward-facing holes and starting over.
Weight removed from the outer faces places the actual center of gravity on a line between the crankpin and the balance holes, which will be a diagonal rather than a vertical line. As the flywheel spins up, the mass of each side tries to rotate around its center of gravity rather than its shaft center, and this imbalance produces vibration, and flexes each crankpin and shaft taper in its hole by bending.

[d_lasher]

It's been awhile. Last weekend we got a chance to go hunting for parts at the 'Dirty Dog Roadhouse' swap meet in Golden CO. It was pretty small and we didn't find any of the parts we were looking for. But, right away we caught a glimpse of a early Indian Chief with a cannonball number on it! We went right to it and started talking with owner. Turns out it's gharper from here. What a small world. Even though we didn't find any parts we needed, we got a ton of information, tips and advise. We talked, actually I asked questions and he answered them, for at least an hour. We even got a ride in his side-car! What a nice guy.

This last weekend it was back to work. All I managed to do this weekend was assemble the connecting rods and bearings and test fit everything. First, I had to hone out the rod's big ends so I could push the race in. Then I built a tool to push the races in. I swear I spend more time making tools then using them. I spent all day Saturday and most of Sunday making the push tool. It had four parts, a base for the rod to sit on. A sleeve that fit in the rod and held the race to keep it square. A collar to push against the race and fit inside the female end of the rod. And a push rod to keep every thing square and together.

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You can even just make out the 0.030" grove in the collar to have the race stick out 0.030" of the male connecting rod. l'll put drawings up on my blog, https://www.thecastlehillgarage.com/the-workshop soon.

After I got the race's pushed in I had to hone the races to fit the bearings. The whole process takes me forever. It's the measuring that takes so long. I'm so worried about overshooting the diameter, I have to measure it ten times every 5 minutes. Hone, both ways, clean it up, take it to the workbench and measure it 10 times frontwards and backwards and then repeat the process again and again. All to take 0.002 inchs out. I could never do this for a living, I'd go broke.

I did manage to mock up the flywheel yesterday. Today I'll start balancing them.

WTR : 66

[d_lasher]

The flywheel work didn't pan out. In order to balance the flywheels I need to assemble the connecting rods and one piston. But the big end bore was 0.005 over the OD of the brand new races I have. I guess I'm supposed to hone out the big end of the connecting rods to fit. I'm thinking I need to bore them out to an interference fit of 0.0015-0.0020, unless someone knows better.

Either way I have to wait because I don't have the right size hone stones to fit. So I'll have to order them and wait.

I decided to leave the land of thousands and move back to the land of close enough. I went back to my rear hub. I last worked on the rear hub back when I was just going to ride around town on the bike, not drive it across the country. I have a 28' scout rear hub with the ball bearings instead of the roller bearings. And all of the races we're iffy.

So I decided to get the bearing races out of the rear hub. Here's how not to do that. 1) Use a big hammer and a drift through the axial at an angle. Result: Nothing happens. 2) Use a 20 ton press with the drift catching the lip of the race to push out. Result: Heat treated race shatters into a million pieces. 3) Use a dremal to cut it out. Result: Would have ruined the hub case. 4) Go to harbor freight and buy a 'Rear Axle Bearing Puller Set'. Result: Get home and find out it's too big. 4) Give up and call it a day. Result: Frustration.

Wake up the next day and sit and think for all of 5 minutes. 5) Cut a 2 inch piece of 1/8 inch piece of flat steel bar. Drop it down the axial flat on the back of the bearing. Push it out with the press. Took about 15 minutes all together and both races came out with out any drama at all.

I think T. Cotten said in another post some where, only the Harley guys use hammers. I should have listened.

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WTR : 68

[d_lasher]

69 WTR

This was a good weekend. I got the cam bushings and gears all setup and ready to go. I used gharper's advice on the lapping compound and using the oil drive gear to drive the gear train, but it was hell on my hands so I changed it up a bit. I put a bolt through the magneto gear and drove the gear chain with a wrench.

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Then I decided to deal with the pinion and drive shaft races. The pinion race was not only heavily pitted but it was also not all the way into the housing and the thrust washer behind it was loose. So I decided to go against kitabel's advice and replace it. So I put the crankcase in the oven at 275 for an hour. When I pulled the case out and put it on the ground to push the race out, it just fell out. I was a little worried about getting the new one back in inline with the drive race. So I decided to make a tool to push the pinion race in through the drive race.

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It worked like a charm. It's always a good sign when you spend an hour making a tool you only use for a minute. Put the case into the oven and the push tool with the race on it into the refrigerator for an hour. Assembled the case and pushed the pinion race in with the pushing tool through the drive race. Just like that it was in and straight.

For the drive race I decided against pushing it out. The first rule of the workshop is 'Don't make it worse'. I was worried I'd make a mess of things trying to push a new one in. So, instead I honed out the race 0.0015 inches, I'll make up for it with over-sized roller bearings. That took most of the pitting out. What remains should be OK. As kitabel suggested the pitting isn't connected and the oil layer should keep the bearings protected.

Now it's on to the flywheels.

[d_lasher]

It’s been awhile, I was on vacation for a little bit, and then had to travel for work. I realized this weekend I never took the time to upload pics of my project. I’m calling him Oscar, Oscar the bastard. Here’s his picture when I first got him home.

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And my current progress,

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I changed his name to Oscar the bastard because everything on the bike was wrong, missing, or broken. Just as an example, a few magneto parts came up for sale on eBay this last week so I decided to crack open Oscar’s and see if I needed them. Here’s a picture of Oscars magneto with the cover off,

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See anything missing, like a magnet or a winding? I guess I’ll add them to my show stoppers list.

More later...

[BoschZEV]

Don't forget to divide by two when turning down.

You need a direct reading dial on your lathe. Not only are the divisions further apart, if you want to reduce the diameter by 0.003" you dial in 0.003", not 0.0015". Or should that be 0.006"?...

I'm sure my lathe's direct dial has saved me countless times.

[d_lasher]

74 WTR (Weekends To Race)!

I got the bronze stock I needed to make the bushings last week and finally had time to make some this weekend.

You read the Internet and listen to the old timers and you get the feeling you can just whip these out in a few minutes. Well not for me. It's measure, measure again, math and cut. Then measure, measure again, math, measure, more math, measure then cut. And measure, crap forgot to divide by two. Start over again.

Lessons learned:
Don't do the math in your head!
Don't forget to divide by two when turning down.
Don't put the bushing back in the lathes' jaw after you've turned down the ID and OD. You'll squeeze it out of shape.
Get a chair and sit, I think better sitting down.

Any way I got the transmission main shaft bushings all done and pushed into the clutch basket and drive gear. I honed the sprocket side bushing to 0.0015 and the clutch side to 0.001. They both fit nicely.

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I'm half way done with the cam case bushings. I'm hoping I can finish these this week, because I'll be gone the next few weekends for vacation and work.

Just a quick pic of my 1932 South Bend lathe and the transmission all ready to be put back together.

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